The aim of this study was to assess, for the first time, the concentrations, sources, dry deposition and human health risks of polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons (AHs), poly-chlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in total suspended particle (TSP) samples collected in Bizerte city, Tunisia (North Africa), during one year (March 2015eJanuary 2016). Concentrations of PAHs, AHs, PCBs and OCPs ranged 0.5e17.8 ng m À3 , 6.7e126.5 ng m À3 , 0.3e11 pg m À3 and 0.2e3.6 pg m À3 , respectively, with higher levels of all contaminants measured in winter. A combined analysis revealed AHs originating from both biogenic and petrogenic sources, while diesel vehicle emissions were identified as dominant sources for PAHs. PCB potential sources included electronic, iron, cement, lubricant factories located within or outside Bizerte city. The dominant OCP congeners were p,p 0-DDT and p,p 0-DDE, reflecting a current or past use in agriculture. Health risk assessment showed that the lifetime excess cancer risk from exposure to airborne BaP was negligible in Bizerte, except in winter, where a potential risk to the local population may occur.

Soils are amajor reservoir of semivolatile organic pollutants such as polychlorinated biphenyls (PCBs) and polycyclicaromatic hydrocarbons (PAHs), and exert a control on their atmospheric occurrence. We present here anassessment of the atmospheric occurrence and seasonality of soil/snow-air partitioning and exchange of PCBs,PAHs, hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCHs) in the arctic city Tromsø, northernNorway. The fugacities of the organic pollutants in soils and snow were determined using a soil fugacity samplerby equilibrating the air concentrations with those in the surface soil/snow. The concentrations in soils did notshowa significant seasonality. Conversely, the ambient air concentrations and the soil (or snow) fugacity showeda clear seasonality for PCBs, HCH, HCB and some PAHs, related to temperature. Fugacities in soil/snow were correlatedwith those in the ambient gas phase, suggesting a close seasonal air-soil/snow coupling. Generally, therewas a net deposition or close to equilibrium conditions during the winter, which contrasts with the net volatilizationobserved during the warmer periods. The chemicalswith lower octanol-air partition coefficients showed alarger tendency for being volatilized and thus remobilized from this coastal arctic environment. Conversely, themore hydrophobic compounds were close to air-soil/snow equilibrium or showed a net deposition.

Occurrence of α , ω -dicarboxylic acids and ω-oxoacids in surface waters of the Rhone River and fluxes into the Mediterranean Sea

A comparative study for 62 toxic chemicals based on the monthly simultaneous collection of aerosol samples during 2015-2016 in two coastal cities at both the African (Bizerte, Tunisia) and European (Marseille, France) edges of the W Mediterranean basin is presented. Legacy polychlorinated biphenyls (Σ18PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (Σ17PCDD/Fs) show generally higher median levels at the African edge (2.1 and 0.2 pg m-3, respectively) compared to the European coastal site (1.0 and 0.08 pg m-3, respectively). Contrary, the “emerging” polybrominated diphenyl ethers (Σ27PBDEs) median concentrations were higher in Marseille (~ 9.0 pg m-3) compared to Bizerte (~ 6.0 pg m-3). Different past usage and current emission patterns were found at both edges of the W Mediterranean, most probably linked to the respective different regulatory frameworks for toxic chemicals. Our results indicate that the total organic carbon (TOC) and/or the elemental carbon (EC) contents in the atmospheric aerosol may have a stronger effect than the total suspended particle (TSP) content as a whole on the spatial-temporal variability and the long-range atmospheric transport potential of the studied POPs. A “jumping” of the PBDE local atmospheric stocks from the NW European Mediterranean edge to the NW African coast seems to be possible under favorable conditions at present. While a higher PBDE median loading is estimated for Marseille area (~ 550 ng m-2 y-1) compared to Bizerte (~400 ng m-2 y-1), the median PCB and PCDD/F dry deposition fluxes were higher at the African site, resulting in a 3-fold higher toxic equivalent (TEQ) loading of dioxin-like pollutants (400 pg TEQ m-2 y-1) compared to Marseille (~140 pg TEQ m-2 y-1) with potential implications for the aquatic organisms. However, the inhalation exposure assessment points to a minimum risk for human health at both sites.

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers and have been detected ubiquitously in the remote atmosphere. Fourteen OPEs were analyzed in 115 aerosol phase samples collected from the tropical and subtropical Atlantic, Pacific, and Indian Oceans during the MALASPINA circumnavigation campaign. OPEs were detected in all samples with concentrations ranging from 360 to 4400 pg m–3 for the sum of compounds. No clear concentration trends were found between the Northern and Southern hemispheres. The pattern was generally dominated by tris(1-chloro-2-propyl) phosphate (TCPP), although tri-n-butyl phosphate (TnBP) had a predominant role in samples close to continents and in those influenced by air masses originating in continents. The dry deposition fluxes of aerosol phase ∑14OPE ranged from 4 to 140 ng m–2 d–1. An estimation of the OPE gas phase concentration and gross absorption fluxes by using three different sets of physical chemical properties suggested that the atmosphere–ocean diffusive exchange of OPEs could be 2–3 orders of magnitude larger than dry deposition. The associated organic phosphorus inputs coming from diffusive OPE fluxes were estimated to potentially trigger up to 1.0% of the reported primary production in the most oligotrophic oceanic regions. However, the uncertainty associated with these calculations is high and mostly driven by the uncertainty of the physical chemical properties of OPEs. Further constraints of the physical chemical properties and fluxes of OPEs are urgently needed, in order to estimate their environmental fate and relevance as a diffusive source of new organic phosphorus to the ocean.